[lldb] Fix compilation with gcc-6.5
This fixes (works around) two errors with gcc-6.5.
- in the RegisterContext_x86 files, gcc is unable to synthesize a
default constructor -- it thinks it needs to initialize the virtual
base class, even though said classes are abstract. I fix that by
providing a dummy constructor.
- In ReproducerInstrumentationTest, it is not able to deduce that the
TestingRegistry class is movable (it contains a map of unique
pointers). I change the type from Optional<TestingRegistry> to
unique_ptr<TestingRegistry), so that moving is not required
(copying/moving a polymorphic type is not a very good idea in any
case).
GitOrigin-RevId: 3bea7306e8669f94bacafae68748a9139cfc0b98
4 files changed
